In recent decades, popularity of folding bicycles has grown significantly as populations increase in density and reliance on public transportation. Public transportation often fails to deliver commuters precisely to their respective destinations. Accordingly, most people using public transportation must resort to walking for a relatively small, yet significant, distance. Bicycles tend to be unsatisfactory adjuncts to public transportation since bicycles are relatively large and bulky items which cannot be easily carried on public transportation such as buses and trains.
One substantially successful transportation mechanism for bridging the gaps in public transportation for individual commuters is the folding bicycle. Currently available folding bicycles can fold to sizes smaller than a typical small suitcase and yet ride nearly as easily as a regular bicycle. To achieve such small sizes, folding bicycles typically involve intricate and complex mechanical solutions. One area in which substantial attention in devoted is that of the handlebars.
Most folding bicycles either use a folding handlebar stem or require that the front wheel and tire be removed for complete folding. Removing the front wheel of a bicycle can be awkward, especially for a commuter, since the removed wheel is a detached piece of equipment that must either (a) somehow be attached to the rest of the folded bicycle or (b) be carried separately. Designing the handlebar to be foldable introduces weakness and perhaps unwanted play and movement in a critical structural part of a bicycle.
Folding handlebars date back to the early history of the bicycle and yet tend not to be used in folding bicycles. Early attempts at folding handlebars were to allow for adjustable riding positions. Examples include folding handlebars described by U.S. Pat. No. 864,202 to Simmons (Aug. 27, 1907); U.S. Pat. No. 3,863,521 to Gatsos et al. (Feb. 4, 1975); and U.S. Pat. No. 5,737,967 to Hartley (Apr. 14, 1998). These folding handlebars focus on adjustability while riding and provide little, if any, reduction in size.
On the other hand, folding handlebars which are designed to reduce the size of a bicycle or other vehicle for storage and/or carrying typically rely on mechanisms external to the handlebars and/or introduce weakness and movement in a critical structural component of the vehicle. Mechanisms external to the handlebars (e.g., U.S. Pat. No. 4,634,138 to Fryer et al.—Jan. 6, 1987) such as external spring latch handles pose risks for snagging clothing while riding.
More important, however, is the introduction of weakness and movement into a critical structural component of a bicycle. Handlebars of a bicycle bear heavy loads. In particular, more aggressive contemporary riding styles, e.g., in urban and off-road riding, place a rider's weight more forward with substantial weight over the handlebars. In addition, any bumps or shocks at the front wheel are typically translated directly to the handlebars. While other front-end components are positioned to handle substantial vertical loads of shocks and bumps to the front tire, handlebars literally stand out as the component to handle such loads transversely. Accordingly, handlebars are a structurally critical component of a bicycle, and they must handle transverse loading.
Most conventional folding handlebars introduce a folding mechanism which allows for folding in precisely the transverse direction in which loads are borne. One example is described in British Patent No. 7578 (1891) to Parkes et al. in which handlebars slide out of a tube to expose a joint about which the handlebars fold. In sliding in and out of a tube, the handlebars require a clearance, however small, to allow for such sliding. Such a clearance, however small, introduces play in the handlebars such that the handlebars are capable of movement independent of the remainder of the bicycle and independent of the sliding motion required to fold the handlebars. In particular, such introduces play transverse to the handlebars. Such play, during rugged riding, can cause excessive wear in the handlebars, can cause weakness in the handlebars, and can be annoying to the rider.
What is needed is a folding handlebar, e.g., one suitable for use on a bicycle, which allows virtually no play transverse to the handlebar and which handles transverse loading virtually as well as a conventional, non-folding handlebar.